When the small painting with a slightly damaged surface and cracks in its wood backing materialised in September at an auction house in New Jersey, no one expected great things. First and foremost was its murky provenance: The name of the artist was unknown, and so was the date of its creation. The auction house estimated that the work would sell for $500 to $800.

“We had no idea when it came up to sale that there were about to be fireworks,” said John Nye, who runs the Bloomfield, N.J.-based Nye and Co.

In a matter of months, the seemingly unremarkable painting would become the talk of the international art world after it was judged to be a long-lost work by the 17th century Dutch master Rembrandt van Rijn.